A strip of 41 squares is numbered 0,1,2,…,40 from left
to right and a token is placed on the square marked 0. Pinar
rolls a pair of standard six-sided dice and moves the token right a number of squares equal to the total of the dice roll. If Pinar rolls doubles, then she rolls the dice a second time and moves the token in the same manner. If Pinar gets doubles again, she rolls the dice a third time and moves the token in the same manner. If Pinar rolls doubles a third time she simply moves the token to the square marked 36.
The expected value of the square that the token ends on can be expressed as a/b where a and b are coprime positive
integers. What is the value of a+b.
Continued from
http://www.jiskha.com/display.cgi?id=1373027417
Can you show an idea of your probability tree to make sure that your interpretation corresponds to what was asked?
What did you get for your answer?